Control system for refrigerant condensing units



.Sept.8,1 ?53 w. F. BORGERD 2,65

CONTROL SYSTEM FOR REFRIGERANT coupxzusmc unrrs Filed Dec. 29, 1950 Patented Sept. 8, 1953 CONTROL SYSTEM FOR REFRIGERANT CONDEN SING UNITS William F. Borgerd, Evansville, Ind., assignor to International Harvester Company, a corporation of New Jersey Application December 29, 1950, Serial No. 203,449

3 Claims. (Cl. 624) The present invention relates generally to'a control system and more particularly to a control system for regulating the spraying of water over the exterior surfaces of an air cooled condenser Or an evaporative condenser.

By providing a refrigeration system with means for sprayin water over the exterior surfaces of an air cooled condenser, the condenser can be quickly cooled from excessively high temperatures. The condenser is normally cooled by air and the water is only used during abnormally high load periods such as might be occasionally encountered during hot summer months. In areas where water is expensive or scarce air cooling of the condenser is very desirable. As the water is sprayed over the hot surfaces of the condenser it absorbs heat therefrom and is evaporated which effectively cools the condenser. Since many refrigeration systems are designed so as to require a minimum of attention from an operator, it is desirable to provide a water spray system with control means for automatically regulating the flow of spray water over the condenser. It is understood that this water should be relatively free of minerals since intermittent operation tends to form deposits more readily than if abundant spray water is constantly used. The control means may be responsive to either the high side pressure or high side temperature since both will rise during overload conditions. It, has been found that control means responsive to the high side temperature are more practical since they can be positioned adjacent a member of the high side without the necessity of connecting into the refrigeration system. This permits ease of assembly and reduces the cost of servicing since it is not necessary to disturb the refrigeration system.

One object of the present invention is to provide a refrigeration system with a water spray system for cooling an air cooled condenser during overload conditions.

Another object of the invention is to provide the water spray system with a solenoid inlet valve which regulates the flow of water through the system.

A further object of the invention is to provide thermostatic means, positioned adjacent a high side member of the refrigeration system, for controlling the solenoid inlet valve so that the How of Water is regulated in response to the temperature of the high side.

A still further object is to provide arefrigeration system with an overload protector which will automatically stop the operation of the system when the high side temperature reaches a predetermined maximum temperature.

water changes from a liquid to a vapor, only a relatively smally quantity of water will he need- Other objects and advantages of the invention will appear as the description proceeds, reference being had to the accompanying drawings wherein a preferred form of the invention is shown. It is to be understood, however, that the drawing and description are illustrative only and are not to be taken as limiting the invention except in so far as it is limited by the claims.

The single figure of the drawing is a diagrammatic view of a refrigeration system provided with an automatically controlled water spray system.

Referring to the drawing for a more detailed description of the invention, a refrigeration system is diagrammatically shown comprising a motor-compressor unit I0, an air cooled con- ..denser II, and an evaporator l2. After the refrigerant gas is compressed by the motor-compressor unit I0, it passes through conduit I3 into condenser II where it flows through the finned tubes of the condenser and loses heat to the cooling air which is circulated over the exterior surfaces of the condenser. The refrigerant gas is condensed in the condenser and then flows through conduit I4 to expansion valve I5 or other pressure reducing device where it passes from the high side to the low side in the usual manner. From expansion valve I5 the refrigerant flowsthrough conduit I6, evaporator I2 and conduit I 1 into the motor-compressor unit to repeat the cycle. The evaporator is adapted to be placed in an enclosure to be cooled, and the air to be conditioned is passed into heat exchange relationship with the exterior surfaces of the evaporator. That part of the refrigeration system comprising the motor-compressor unit I0, conduit I3, condenser I I and conduit I4 is commonly termed the high side of the system since the refrigerant in these members is maintained at a high pressure. The refrigerant in conduit I6, evaporator I2 and conduit I1 is maintained at a low pressure and this part of the system is termed the low side.

' Positioned adjacent the condenser I I is a spray nozzle l8 from which a fine spray of water may be ejected onto the exterior surfaces of the condenser II. During normal operating conditions, the condenser will be cooled only by the cooling air which circulates thereover. However, if overload conditions are encountered, the temperature and pressure of the high side willrise. As water is sprayed over the condenser II by nozzle I8, the water will absorb heat from the hot surfaces of the condenser and be evaporated. Since considerable heat will be removed as the l8. The valve comprises a valve body havin'ga water inlet 2| and a water outlet-22. wA rubber hose 23 connects the water inlet 2! to iaisuitablewater supply and a second rubber hose ,24 connects the water outlet 22 to'the-spraynozzleilt." The valve body 20 is provided with an inletc'ha'mber 25 and an outlet chamber 26 which are separated by a wall memberi-ZT. A cvalve port flfi extends through wall member 21 and is provided with a conical shaped valve seat 29. A conical shaped valve member 3G-is positioned above valve =-'seat 29 so that itmay-be moved into engagement -"with the valve seat inorder to'close valve-port "28. I'he-valve member-30 is also adapted-tube moved away from thevalve seatf29 which opens the'valve port 28'. The lowerendof a vertically extendingvalve stem -3! is secured to valve mem- 'b'e'r 3!l and 'the upper end-isprovided with a'circular shaped head 32-. 'The valve stem extends upwardly through an-opening-"BS' provided in valvdbodY 20.

' Amen-magnetic cylindrical shaped housing 34 encloses the upper portion of the valve stem with --'the =lower- 'openend 'fitted into opening '33 and secured to valve body 29'- in sealed relationship. :Aii 'energizing-coil '35 is disposed'about the housing 34 and s'ecured thereto in any suitable man- Deli- A cylindrical shaped armature member or 'plunger36 is disposed within'the housing 34 and is reciprocally movable therein upon energization or' deenergization ofthe coil -35. The 1 plunger +38- is'provided with an internal bore 3'! which fits over-valve stem 31 in sliding relationship. '-When the coil 35'is riot-energized, the'lower end 3B of-the plunger will contact member 353 and the'weight of valve'member 30, valve stem 3| -and plun'g'er 36 'willforce the valve member into -engagement-with valve seat 29. This closes the valve port 28- and prevents water from flowing th'ei ethrough. When the coil--35 is energized, a mag-netic field is setup which lifts plunger 85. In itsuupward' travel the plunger -35 strikes the valve stem head -32 a" sharp blow and moves the valve' stem 3| and valve member '35 upward. .As :the valve m'ernber iiii moves awayfromvalve seat "'29ithevalveport ZB will be opened and water willliowtherethrough.

T Theelectric circuit for the coil 35 andthei le'ctrio-motor of motor-compressor unit l llcomprises a room thermostat *39, thermostatic switch-.49, -:'-electric'al resistor 41 fand thermostatic switch '42. "The-room thermostat '39 ispositioned within' the fienclosure containing evaporator [2 so that" it will be subjected to'the temperatures of the air "being conditioned. In the-"illustrated embodiment the thermostatic switches!!! and 42 and resistor 41 are all mounted in close, proximity to the motor-compressor unit. Theycould be 'p'ositioned within a-small housingattached' to a portion oi the compressorso that they wouldbe, subjected to the temperature of the high side.

Room thermostat fie'com'prises .fixed contact "43 and {contact 44 whichis 'securedtothemova'ble end of a bimetallic strip "45.Wire 46 connectscontact"43' to a suitable electric supply source. 5 Thermostatic switch 4t comprises jfix'ed -contact '41; movable contact 48 and a bimetallic strip '49. Gontact' 48 is-secur'ed tothemotable end of bi-metallic strip at and is electrically connected by wires 58 and 5! to contact 44 of the room thermostat 39. Terminal 52 of coil 35 is connected to contact 41' by wire 53 and terminal 2 54 is connected'to the power supply by wires 55 and 56. The motor-compressor unit'lil is connected in parallel with the coil 35 by wire 51, thermostatic switch 42, resistor 4|, wire 58 and :wire 59. v The switch 42 comprises fixed contact m' -iiilliand, contact 8! which is mounted on the mov- .able end. of a bi-metallic strip 62. Switches and 42 are mounted adjacent resistor 4! so that 'theth'eatgener'ated by the resistor will affect the bi-metallic strips 49 and 62.

The: operation of the system will now be explained. When the temperature of the enclosure in which the evaporator I2 is positioned has risen to ,a predetermined value, the bi-metallic strip 'of roomthermostat 39 will bend and contact willbe moved into engagement with contact "'43. If the-temperature of the high side is within a normal range, bi-metallic strip 62 of switch '42 will be bent so that contact El will be in engagement with contact-"69. This completes thecir- 25 cuit to motor-compressor unit I9 from the power supply through wire45, room thermostat 39, wire -5l;-wire 5?,th'ermostatic switch 42, resistor Al and wire "58, and back to the power supply through wires 59 and'56. As the circuit is comopleted; the refrigeration system will begin to goperate and the air within theenclosure will-be cooled' as it circulates over the evaporator l2.

If the-condenser I! does not properly coolthe "refrigerant, the high side pressure and tempera- 35 'turewill-rise and resistor 4| will be heated due to the increased-current 'ilow to'the motor-coin- "pressor unit 10. The heat from the resistor 4| and motor-compressor unit it will cause'the bimetallicV-strip 49 of switch 40 to bend until contacts 3T and-48 are touching. This completes the "circuit tothe coil 35 from the power supply through wire'tt, room thermostat 39, wire 5!, wirebflgthermostatic switch' iil and wire53, and back to the power supply through wires 55 and 55. As-thecoil 35' is energized, plunger 35 will belifted upward and valve'member 35 will be -moved away from valve seat 29. This permits -water to flow through valve port 28' to spray nozzlelii, from which it will be sprayed onto the condenser l l. --Nozzle 18 will continue to'spray water onto'the condenser until the high side tem- "pera-tureis lowered to .a safe operating range. -Bi-metallic strip 49 of switch 48 will then bend until contacts 41 and 45 are apart which breaks the circuit'to the 001135. Coil 35 is then deenergized which closes valve port 28 and stops the flow of water to nozzle Hi.

If forsome reason a water supply does not exist inhose'23, 'no relief from the excessive load 50 conditions will occur and the temperatures of the -high-S'ide andresistori li will continue to rise runtil' bi-metaIlicstrip'GZ of switch 42 has been sub- "J'ected =-to a predetermined temperature which causes it to bend and move contact SI away from 65 contact-'60. This breaks the circuit to themotorcompressor unit in and stopsthe refrigeration system. 'After thetemperature of the high side "has returned'to a safe operating range, the bimeta'llic strip- GZ'WiII-bend to its original position with contact 68 in engagement with contact "6|. "Manual meansmay lye-provided for resetting 'switch'flzafter the operator has located the reason for no water'supply. Since the coil 35 is con- -'-nected=- in-' parallel with the motor-compressor unit I0, water will continueto"spray"from the nozzle I8 until the temperature of the high side has been lowered. It may be desirable to direct part of the water spray over the motor-compressor unit In in order to insure that it is cooled as rapidly as the condenser I I.

As can be understood from the preceding description, a refrigeration system is provided with a water spray system which will effectively cool an air cooled condenser during overload conditions. The solenoid valve l9 will effectively regulate the flowv of water over the condenser l I, and the thermostatically controlled circuit will accurately control the valve in response to the temperature of the high side. In the illustrated embodiment, the switch 40, resistor 4| and switch 42 are shown positioned adjacent a portion of the motor-compressor unit, but it is to be understood that they could be positioned adjacent any other member of the high side that is responsive to high side temperature and pressure, such as conduit 13 or condenser H. While only one form of this invention has been disclosed, other forms thereof may become apparent to those skilled in the art upon reference to this disclosure and therefore this invention is to be limited only by the scope of the appended claims and prior art.

What is claimed is:

1. In a refrigeration system, the combination of a hermetically sealed casing, a compressor, a motor for the operation of said compressor, said motor and said compressor mounted within said hermetically sealed casing, a first circuit for connection to a power source, said first circuit including a thermostatic switch, a resistor, and said motor, said resistor formed to radiate quantities of'heat proportional to the current therethrough, said thermostatic switch mounted in close proximity to said hermetically sealed casing and said resistor, 50 that any heat radiated by said resistor and any heat radiated by said hermetically sealed casing will be radiated to said thermostatic switch, a condenser connected to said compressor, water spray means for cooling said condenser, a solenoid valve for controlling the operation of said spray means, a second circuit for connection to said power source, said second circuit including a second thermostatic switch and said solenoid valve, said second thermostatic switch positioned in close proximity to said resistor, so that any heat radiated from said resistor will heat said second thermostatic switch, said first thermostatic switch being biased so that the contacts thereof are closed when the heat radiated from said hermetically sealed casing and the heat radiated from said resistor are in a normal range, said second thermostatic switch being biased so that the contacts thereof are open when the heat radiated from said resistor is in a normal range.

2. In a refrigeration system, the combination comprising a motor-compressor unit mounted within a hermetically sealed casing, a condenser, an evaporator, metering means, tubing means connecting said evaporator, said metering means, and said condenser in series to said compressor, a header having a plurality of spray nozzles mounted thereto, said header mounted adjacent said condenser, a source of water connected to said header, a valve for controlling the supply of Water to said header, a solenoid connected to said valve for the operation thereof, said solenoid connected to said valve so that said valve is opened to permit water to be supplied to said header when said solenoid is energized, a first circuit for connection to a power source, said first circuit including said motor, a resistor, and a thermostatic switch connected in series, said thermostatic switch positioned in close proximity to said hermetically sealed casing and said resistor, said resistor formed to radiate quantities of heat proportional to the current therethrough, said thermostatic switch being biased so that the contacts thereof are closed when the quantity of heat radiated thereto by said resistor and by said hermetically sealed casing is below a predetermined amount, a second circuit for connection to said power source, said second circuit including a second thermostatic switch and said solenoid connected in series, said second thermostatic switch positioned in close proximity to said resistor, said second thermostatic switch being biased so that the contacts thereof are open when the heat radiated from said resistor is below a certain predetermined amount.

3. In a refrigeration system, the combination comprising a motor-compressor unit mounted within a hermetically sealed casing, a condenser connected to said compressor, water spray means for cooling said condenser, a solenoid valve for controlling the operation of said water spray means, said solenoid valve formed to permit the operation of said Water spray means responsive to the energization of said solenoid valve, a first circuit for connection to a power source, said first circuit including said motor, a resistor, and a thermostatic switch connected in series, said thermostatic switch positioned in a heat exchange relationship to said hermetically sealed casing and to said resistor, said resistor formed to radiate quantities of heat proportional to the current therethrough, said thermostatic switch being biased so that the contacts thereof are closed when the quantity of heat transferred thereto by said resistor and by said hermetically sealed casing is below a predetermined amount, a second circuit for connection to said power source, said second circuit including a second thermostatic switch and said solenoid valve connected in series, said second thermostatic switch positioned in a heat exchange relationship to said resistor, said second thermostatic switch being biased so that the contacts thereof are open when the quantity of heat radiated thereto by said resistor is below a certain predetermined amount.

WILLIAM F. BORGERD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,512,793 Palmer Oct. 21, 1924 1,601,477 Kritzer Sept. 28, 1926 1,943,759 Fourness Jan. 16, 1934 2,159,592 Kalischer May 23, 1939 2,185,965 Newill Jan. 2, 1940 2,210,325 Newton Aug. 6, 1940 2,389,073 Newton Nov. 23, 1945 

